Chart-changing apparatus

ABSTRACT

This chart-changing apparatus includes an arbor which is mounted by a central locking screw on a hub attached to the chart drive motor of a recorder. The arbor is provided with flats or splines on opposite sides and an abutment ring at the outer end, while a series of charts having central holes and an interspaced series of washers having slots at one side engageable with the splines are mounted on the arbor, with the outermost washer engaging the abutment ring. The charts and washers are held in position by a spring pushing against a chart disc which rotates with the arbor and is keyed thereto for longitudinal movement. When a pusher is actuated to engage the outermost chart, through a microswitch having a cam follower which will engage a notch in the rear flange of the hub when the arbor is rotated so that the washer slots are uppermost, the outermost washer will drop from the arbor and then the outermost chart will drop off the end of the arbor. The remaining washers are held between the charts by the spring and against the abutment. A series of charts and washers sufficient for a period, such as one month, are mounted on an arbor for replacement of an arbor from which the charts have been removed, by the same central locking screw.

United States Patent Adams I [54] CHART-CHANGING APPARATUS Bobby D. Adams, El Paso, Tex.

Texas Instrument Houston, Tex.

22 Filed: Sept. 10,1970

211 Appl.No.: 71,272

{72] Inventor:

[73] Assignee: I Engineers, Inc.,

Related U.S. Application Data [63] Continuation of Ser. No. 797,116, Feb. 6, 1969, aban- Primary Examiner-Joseph W. Hartary Att0rneyVan Valkenburgh and Lowe, Arnold, White & Durkee and Paul Van Slyke [451 Jan. 25, 1972 [57 ABSTRACT This chart-changing apparatus includes an arbor which is mounted by a central locking screw on a hub attached to the chart drive motor of a recorder. The arbor is provided with flats or splines on opposite sides and an abutment ring at the outer end, while a series of charts having central holes and an interspaced series of washers having slots at one side engageable with the splines are mounted on the arbor, with the outermost washer engaging the abutment ring. The charts and washers are heldin position by a spring pushing against a chart disc which rotates with the arbor and is keyed thereto for longitudinal movement. When a pusher is actuated to engage the outermost chart, through a microswitch having a cam follower which will engage a notch in the rear flange of the hub when the arbor is rotated so that the washer slots are uppermost, the outermost washer will drop from the arbor and then the outermost chart will drop off the end of the arbor. The remaining washers are held between the charts by the spring and against the abutment. A series of charts and washers sufficient for a period, such as one month, are mounted on an arbor for replacement of an arbor from which the charts have been removed, by the same central locking screw.

7. .27. ean-S1 Preaiesfi er v r PATENTEU mzsmz' SHEET1UF4 INVENTOR. Bobby D. Adams A T TOR NE Y8 PVATENTEU was 1912 SHEEY 2 BF 4 FIG. 7

INVENTOR. Bobby D. Adams ATTORNEYS PATENTEB JANZSIQYZ SHEET 3 (IF 4 w FIG. I2

IN VENTOR.

FIG. [3

BY Bobby 0. Adams [f /M 4 1 M ATTORNEYS minnows-ma 3638.235

SHEET-'4 0F 4 FIG. I4

INVENTOR. Bobby D. Adams l/WYM ATTORNEYS CHART-CHANGING APPARATUS This is a continuation of application .Ser. No. 797,1 l6, filed Feb. 6, 1969 and now abandoned. 1

This invention relates to instrument recorders using circular charts, and more particularly to automatic chart-changing apparatus for such recorders.

The invention especially relates to automatic chart-changing apparatus which functions in a cyclic manner to drop the circular charts from the recorder as they are marked by pens or the like about a 360 arc, to thus present an unmarked chart for the next cycle of recording. As such, the present invention is of the same general type as, and is an improvement over, the chart changer disclosed in US. Pat. No. 3,258,778 issued to LeBron Hardie on June 28, 1966.

Circular record charts are used with many types of instruments which measure a continuing physical action where cyclic time intervals, such as an hour, day or week are important. For example, such recorders are especially desirable to record the continuous flow of fluid, such as the flow in a gasline, where a periodic record becomes important to ascertain the volume of gas flowing through a particular line for a given period of time and the resulting charge to the customer. Each circular chart will be marked to indicate a record of the flow for a selected time period, such as 24 hours. After mark ing for such a period of time, it is necessary to remove the chart from the recorder and place another chart upon the recorder to be marked during the next succeeding time period.

The objects of the present invention are to provide a novel and improved automatic chart-changing apparatus which: is a simplified structural and mechanical organization that may be easily adapted for use with various types of commercial recorders using circular charts; is positive in its action, with freely acting components and parts which will not stick or jam to prevent or delay chart-changing operations; operates to change a series of charts at precise time intervals; operates quickly to permit the changer to be used with instruments which cycle in time periods involving minutes, as well as time periods involving hours or days; holds a large number of charts with each chart having its graphic scales positively and precisely correlated with respect to the marking and releasing mechanism of the recorder; involves a quick-change unit including a supply of charts for a desired time period, such as one month, which may be preassembled and installed in the recorder in a minimum of time; may be actuated by a small storage battery where a regular power supply is not available, to operate the mechanism directly or to operate the same in conjunction with a compressed air or fluid supply; and is a neat appearing, compact, low-cost, rugged and durable unit.

With the foregoing and other objects in view, all of which more fully hereinafter appear, my invention comprises certain constructions, combinations and arrangements of parts and elements as hereinafter described and illustrated, in preferred embodiment, in the accompanying drawings, in which:-

FIG. I is a perspective view of a conventional flow meter and of a housing enclosing a circular chart recorder for the meter, with the housing including a chart-retaining pocket and carrying a release actuator component on the window of the housing in accordance with the present invention.

FIG. 2 is an exploded, perspective view of a portion of the instrument housing and of the chart carrier assembly, including a chart-holding arbor which is constructed and arranged according to the present invention.

FIG. 3 is a fragmentary vertical section, taken along line 3 3 of FIG. I but on an enlarged scale, to illustrate the mounting of the release actuator upon the window of the instrument housing and its normal position and association with the chart carrier assembly and the charts thereon.

FIG. 4 is a fragmentary, front perspective view of the release actuator per se, on a further enlarged scale.

FIG. 5 is an exploded isometric view of the chart holding arbor and a lock ring associated therewith.

FIG. 6 is an end view of the chart-holding arbor of FIG. 5, with its lock ring being in place.

FIG. 7 is an isometric view of a chart retainer clip, which is normally carried by the holding arbor between adjacent charts.

FIG. 8 is a small-scale front view of a chart which may be mounted upon the holding arbor, illustrating certain lines normally printed thereon and omitting others, but showing an indexing notch at the peripheral edge.

FIG. 9 is a fragmentary vertical section similar to FIG. 3, but on an enlarged scale, and taken through the axis of the release actuator and chart carrier assembly.

FIG. 10 is a fragmentary section similar to FIG. 9, but showing the release actuator when shifted to release a retainer clip, to initiate a chart-changing operation.

FIG. 11 is a fragmentary section similar to FIG. 10, but showing the release actuator commencing its return movement.

FIG. 12 is a fragmentary section similar to FIG. 11, but showing the release actuator on completion of its return movement and a released chartdropping away.

FIG. 13 is a side elevation of a quick-change unit for the recorder, including a chart-holding arbor and a set of charts thereon, which may be substituted on the drive mechanism of the recorder for an arbor depleted of charts.

FIG. 14 is a diagram of an electrical circuit for operating the actuator by electrical impulses.

FIG. 15 is a partially diagrammatic side elevation of equipment by which the actuator may be operated by compressed air or other fluid, but electrically controlled, such as by the circuit of FIG. 14.

Referring more particularly to the drawings, a conventional flow meter F is associated with a recorder encased within a housing H, as shown in FIG. 1, and supported by a post 15. The recorder includes a conventional flow indicator which controls a pen, not shown, adapted to mark a circular chart C, as best illustrated in FIG. 8, as the chart is rotated by a chart carrier K of FIGS. 2 and 3. The housing H includes a rectangular shell 16 having a backwall 17 adapted to hold the chart carrier K, as well as other components, as hereinafter described. The housing H also includes a rectangular door 18 at its front which is secured to the shell 16 by a conventional hinge arrangement, not shown, and a key-actuated latch 19, for access to the interior of the housing. Door 18 has a transparent window 20 which provides a convenient location for mounting an actuator A. To receive and accommodate charts C as they are marked and dropped from the carrier, as hereinafter described, the housing includes a boxlike pocket 21 depending from the shell I6. The pocket, comparatively shallow, has a width corresponding to that of the shell 16 to accommodate the flat, circular charts. The pocket also includes a suitable latched door 22 at its bottom, for ready removal of the marked charts.

The chart carrier K is mounted upon an outstanding drive shaft 24 of a conventional motor (not shown) which is mounted within a flat, cylindrical case 25. The case 25 includes a circumferential flange 26 which is attached to the backwall 17 of the housing to hold the shaft 24 at a desired position with respect to the housing and thus form a base for the carrier K. The motor within the case, which is not shown, is essentially a clock mechanism adapted to rotate the shaft 24 one revolution for each selected cyclic time period of meter operation, such as, for example, a 24-hour interval. As such, the mechanism of the motor need not be described, since it is conventional.

The chart carrier K includes a short tubular hub 27, normally securely fitted upon the shaft 24 and secured against rotation, as by a setscrew 28, shown in dotted lines in FIG. 2 and in full lines in FIG. 9, which is tightened against the drive shaft 24. This hub, having a threaded socket 29, supports other components of the carrier, as will be described. A flat, circular cam disc 30 is affixed to or integral with the base of the hub, to lie adjacent to the case 25, and a notch 31 is provided at a selected location on the periphery of this disc to initiate cyclic actuation of the chart-changing apparatus, as hereinafter described. A pin 32 extends axially from disc 30,

as at a. position opposite notch 31, for a purpose also described hereinafter.

A cam follower 33 normally rides against the edge of cam disc and is carried by the actuator arm of a microswitch 34, which may be double acting and is secured to the housing backwall 17 by a bracket 35, as in FIG. 2. Accordingly, the microswitch 34 will be actuated when the follower drops into and moves out of the notch 31, as hereinafter described.

A generally cylindrical arbor 37, having a disc-shaped flange 38 at its base, is mounted upon the hub 27, with a countersunk hole 39 fitting over the hub and the flange 38 abutting the face of the cam disc 30, the arbor thus being extended and cantilevered from the hub. Arbor 37 is held in position upon the hub 27 by a lock screw 40, which extends through the outer end of the arbor and into the threaded socket 29 in the hub. The angular position of the arbor upon the hub is maintained by pin 32 which may be secured to disc 30 by press fitting the pin into a hole drilled in the disc, as in FIG. 9, or pin 32 may be threaded into a hole tapped for that purpose. Pine 32 enters a hole 41 extending from the rear side of arbor 37, as in FIG. 9.

The arbor 37 has diametrically opposing, flat surfaces 42 which lie in spaced parallelism to the axis of the arbor, as in FIG. 5, these flats 42 being hereinafter referred to as splines because they will be oriented in substantially vertical planes when the chart carrier K is rotated to a chart-changing position and function to permit the charts C and a backing plate 43 to slide along the arbor and release clips 44 to drop from the arbor, as hereinafter further described. Each clip, as in FIG. 7, is shaped generally as a flat washer having a slot 45 extending from one side and past its center to fit upon the arbor 37 with the parallel sides of slot 45 embracing the splines 42 of the arbor with a free fit. The opposite round surfaces of the arbor, between the splines 42, are provided with longitudinal key ways 46, for a purpose described below, while an annular shoulder 47 at the outer end of the arbor is adapted to receive a lock ring 48, which has the same outer diameter as the arbor itself, so as to be flush with the cylindrical surface thereof but to form an abutment at each spline 42, as shown in FIG. 6. The locking ring 48 may be secured to the arbor in any suitable manner, as by staking 49 of FIG. 6. Accordingly, a disc-shaped chart C, having a circular hole 50 at its center, is adapted to slidably fit upon the arbor, and move onto or off the arbor without interference by the lock ring 48; however, the backing plate 43 or a release clip 44 which embrace the splines 42 of the arbor will be held against the abutments formed by the lock ring 48.

The chart backing plate 43 is formed as a rigid, thin-walled disc and is mounted upon the arbor 37, as in FIg. 9. Thus, plate 43 may be provided with a hub 51, as in FIG. 2, which has a circular center hole 52 in which is installed, at opposite positions, a pair of keys 53 for engagement with key ways 46 of the arbor, as in FIG. 9. Accordingly, the plate 43 may slide back and forth along the arbor, will rotate with rotation of the arbor and will be prevented from sliding off the arbor by the lock ring 48. The plate 43 is resiliently urged outwardly on the arbor, away from the flange 38 and against the lock ring, by a spring 54 which is mounted upon the arbor between the flange 38 and the opposing side of the plate hub 51, as in FIGS. 3 and 9. Flange 38 is provided with an annular groove 55 which receives one end of the spring, while the rear side of hub 51 is provided with a similar groove 56, indicated in dotted lines in FIG. 2 and also shown in FIG. 9. Y

A plurality of charts C, such as 30 or 31 for a 1-month supply, are held upon the arbor by a series of the flat clips 44, which are interspaced between the charts, so that the front clip will easily fall away from the arbor whenever the arbor is rotated to place the splines 42 in vertical position, with the clips on the underside of the arbor, and actuator A is activated, as Shown below. The remaining clips are held in position, being squeezed between charts by pressure of spring 54. It will be noted that the number of charts C shown in FIGS. 3 and 913 is illustrative only, since the number of charts on the arbor will depend on the number originally placed on the arbor, which will normally depend upon the number of days in the month or other period of time, and the number which have been dropped off.

Whenever charts are mounted upon the arbor, they will all be rotatively oriented upon the backing plate by a pin 58 outstanding from the backing plate 43 by fitting the pin 58 into a notch 59 in the edge of each chart. On each chart C, the pen will mark the flow at any given time in the area between an inner circle 60 and outer circle 61 of FIG. 8, while the charts conveniently include time marks 62 around the outer periphery, with appropriate indicia showing the time, as for a 24-hour period. The uppermost hour mark 62 of FIG. 8 is 12 noon, while notch 59 is shown as located at 1:15 p.m., for a purpose hereinafter described. A plurality of charts are mounted upon the arbor, as indicated and as shown in FIGS. 3 and 9. The inner chart C is placed to abut the backing plate 43, then a clip 44 for the innermost chart is mounted on the arbor, a second chart C placed against the first clip, then another clip and yet another chart, and so on until the arbor is loaded with the desired number of charts, with a clip between each two adjacent charts and with the outermost clip being held by spring 54 in position against the lock ring 48, and holding the outermost chart in position. As long as the pressure of the spring 54 holds the outermost clip against the lock ring and the other clips between the charts, the entire assembly will remain in position. Of course, before placing any charts or clips on the arbor, spring 54 and then the backing plate 43 is placed thereon with keys 53 in key ways 46, and lock ring 48 placed in groove 47 and secured to the arbor, as by staking or any other suitable manner.

When the arbor is so loaded with charts, he quick-change unit U of FIg. 13 is produced, comprising merely an arbor 37, a backing plate 43, a spring 54, a lockring 48 and a sufficient supply of charts C with accompanying clips for a period, such as one month, to permit thevacant arbor to be removed by removal of screw 40 and installation of the unit U through use of the same screw 40. Since the recorders may be located at remote places, and spaced apart different distances, an opera tor may preassemble the number of units U for the recorders whose charts are to be changed during 1 day or during one trip and quickly substitute the unit U for he vacant arbor, at the same time picking up the marked charts which have fallen into pocket 20, and then moving to the next recorder. It will be noted that charts need not be replaced at all recorders at the same time, but that the time of day may vary to provide a more convenient trip for the operator. Thus, the charts may be installed at times such as 1 hour or 2 hours apart. Thus, one unit U may be assembled with charts whose notches 59 are located at 1:15 p.m., as shown in FIG. 8, for a recorder at which the charts are changed at 8:00 a.m., but for another recorder whose charts are changed at 9:00 a.m., the notches 59 of the charts may be located at'a position corresponding to 2:l5 p.m., to accommodate the positionof the pens in an American meter, for instance.

The position of the notch 31 in cam disc 30 should correspond to the cam follower 33 when the charts are to be changed, with the position of notch 31 being determined by the position in which hub 27 is locked on shaft 24 by setscrew 28 of FIG. 9, which, for convenient access, may be placed in the center of notch 31, as shown. Thus, the arbor is placed upon the hub 27 so that the cam notch 31 on the cam disc 30 will be positioned to receive the follower 33 when the splines 42 are vertical and the clips 44 are at the underside of the arbor, as illustrated. The chart C will be marked through a full revolution of the arbor, commencing at this position, and will then be dropped from the arbor. Thereafter, the pen will contact and mark the next chart C in the sequence for a full revolution, before it is dropped off the arbor, as will be described.

The actuator A is conveniently mounted upon the housing window 20 in axial alignment with the chart carrier K, and operates responsive to the tripping of switch 34 heretofore described. The actuator includes a solenoid or like coil, within a cylindrical case 64. As in FIGS. 3 and 4, the case has a flange 65 at one end to permit it to be fastened to the exterior of the window 20, as by screws as shown in FIG. 1. Suitable wire leads 66 extend from this case for connection to an electrical circuit, such as hereafter described. The actuator is adapted to axially extend the armature of this solenoid, which is a rod 67 extending through an opening 68 in the window, and toward the charts on the arbor. A- circular, cup-shaped foot carried upon the end of the rod 67 comprises a short arcuate rim 69 outstanding from the upper portion of a flange 70 of a hub 71 which is mounted on the end of rod 67. Rim 69 is proportioned to push against the outermost chart without engaging a clip 44 and also to permit the outermost'clip to drop off the arbor when the actuator A is stroked from the position of FIG. 9, in which clearance for the marking pen or pens is provided, to the position of FIG. 10, as indicated by the horizontal arrow. As indicated by the vertical arrow of FIG. 10, when the clip drops, it will be caught in a box-shaped container 72, formed of plastic or other suitable material and removably suspended from the opposite side of flange 70 by pins 73, which engage suitable holes in the rear wall of the container. To provide clearance for the clip 44 as the rod 67 moves toward the charts, the upper front edge 74 of the container is concave, as in FIG. 4. After the outermost clip 44 drops, as in FIG. 10, the rod 67 will be returned, moving in the direction of the arrow of FIG. 11, with the charts following the pusher and held in contact with rim 69 by spring 54. Since the outermost clip has dropped off, the outermost chart C will follow the pusher across the lock ring 48, since hole 50 in the chart is larger than the lock ring. Thus, the outermost chart will move off the end of arbor 37 and will then drop, as shown in FIG. 12 and indicated by the arrows, to fall into pocket 20. As the outermost chart drops, it will slide from beneath the marking pens. Due to the fast action of the pusher in returning the outermost chart will normally drop so fast that no extraneous marks of the pen will be found thereon. While the outermost chart, thus released, drops off the arbor, the next chart will not drop off, because the next clip 44, as in FIG. 12, will abut the lock ring at the splines 42 and the remaining clips and charts will be held on the arbor, through the pressure of spring 54. It will be noted that rim 69 maintains pressure against the charts on its return movement until the next clip 44 engages the lock ring, so that intermediate clips 44 cannot drop off, the as sembly of charts and clips being squeezed between spring 54 and rim 69. After the requisite time interval has elapsed and another chart has been marked, cam notch 31 will again reach the cam follower 33 and the chart-changing operation will be repeated in a similar manner.

In FIG. 14 is shown a diagram of a suitable circuit for effecting operation of actuator A. The switch 34 is shown as a double-acting switch having a normally open contact 78, which is shown in the drawings as closed, because cam follower 33 is shown as having dropped into notch 31, and a normally closed contact 79, which is shown in FIG. 14 as open, for the same reason. Contact 78 is connected to one side of a battery 80, the opposite side of which is connected to a capacitor 81, which is in series with the switch 34. The opposing, normally closed contact 79 (shown open) is connected to a relay solenoid 82 which is connected with the same side of the battery as capacitor 81. A normally open switch 83, controlled by relay solenoid 82, and the solenoid coil 84 of actuator A are connected in series across the battery 80, through wires 66.

When the follower 33 drops into the cam notch 31, to close contact 78 of switch 34, as illustrated in FIG. 14, the capacitor 81 will be charged. Upon moving out of the notch, the contact 78 opens and contact 79 closes. The capacitor 81 then energizes relay solenoid 82 for a short time period, sufficient to discharge the capacitor and to close relay switch 83. Closure of relay switch 83 causes the battery to energize the coil 84 and extend the armature rod 67. However, as soon as the capacitor 81 discharges, switch 83 will open to permit the armature 67 to return and there is no further battery drain until the next chart-changing operation. This time period need be sufficient only to permit a retainer clip 44 to drop away from the arbor, as illustrated in FIG. 10.

Before the operation is repeated, the chart carrier K will rotate a complete revolution, while the outermost chart is being marked with a pen, in a conventional manner. The next cycle is commenced by the follower 33 again moving into the notch 31 to close the contact 78 and charge the condenser 81. Thereafter, as the follower moves out of the notch 31, contact 78 opens and contact 79 closes to repeat the cycle, i.e., to extend the actuator, cause the next retainer clip 44 to drop and then the next chart C to drop, as the actuator returns to its normal position. This cyclic operation may continue as long as charts are available upon the arbor.

In FIG. 15 is shown a modified actuator A. In many instances, the recorders using such charts are located at sources where electric power or large batteries are not always available and where it becomes desirable to use a compact battery which will last for a very substantial period of time. The actuator A of FIG. 15 may include an electrical circuit, such as shown in FIG. 14 and connected thereto by wires 66, as before. However, the solenoid 65' of FIG. 15 merely operates a conventional control valve for an air cylinder 87 to the piston of which actuator rod 67 is connected. A compressed air tank 88 is provided with a filling valve 89 and a turnoff valve 90, from the latter of which a hose 91 extends, through a pressure regulator 92, to air inlet 93 for the solenoid-operated valve controlling the air supplied to cylinder 87. Whenever solenoid 65 is energized, air pressure-is supplied to the cylinder 87 and the actuator rod 67 will be extended to release a retainer clip and a chart the same as heretofore described. When the air control valve is reversed by solenoid 65', air in cylinder 87 will be exhausted through an outlet 94 and the rod 67 will be returned, as by a spring provided for that purpose, although cylinder 87 may be double acting, if desired. As will be evident, the use of the air pressure will greatly reduce the drain upon the battery. As will also be evident, any other readily available gas, such as pipeline gas, may be utilized instead of air.

Have now described my invention in considerable detail; however, it is obvious that others can build and devise alternate and equivalent constructions which are within the scope and spirit of this invention.

What is claimed is: l

l. A chart-changing apparatus adapted to be mounted upon the output drive-shaft of the timing motor of a recorder and to hold a series of charts for marking in turn by a recorder pen or the like as the charts are rotated by the motor, the combination comprising:

a. an arbor having spline means thereon, said arbor being adapted to be mounted upon said drive shaft to extend therefrom;

b. abutment means at the outer end of the arbor interrupting the spline means but permitting charts with a central hole to be moved onto and off the arbor from the outer end thereof;

c. a chart backing plate fitted upon the arbor and constructed and arranged so as to rotate with the arbor and to move longitudinally along the arbor to or from said abutment means;

. means for biasing said chart backing plate towards said abutment means;

e. a series of retainer clips adapted to be interspaced with charts disposed on said arbor, each said clip having means engaging said spline means so as to rotate with the arbor and move longitudinally along the arbor and means to permit the clip to fall away from the arbor under conditions including that when the arbor is rotated to a predetermined position, said clips being normally held in position on the arbor by the pressure of said biasing means urging the outermost clip against the abutment means;

f. actuator means for pushing charts disposed on said arbor away from said abutment means to release the pressure holding the outermost clip against said abutment means; and

g. means for activating said actuator means when said retainer clips and arbor are in said predetermined position, so as to release the outermost clip from the arbor, said biasing means causing the outermost chart to drop off the outer end of the arbor upon a return movement of said actuator means and urging the next outermost clip against said abutment means, so as to hold the remaining charts and clips upon the arbor.

2. A chart-changing apparatus as defined in claim 1,

wherein:

said spline means comprise flat surfaces on opposite sides of the arbor and disposed in spaced parallelism.

3. A chart-changing apparatus as defined in claim 2,

wherein:

said abutment means comprises an annular shoulder at the termination of said spline means; and

a ring mounted on said shoulder, said ring extending laterally beyond the surfaces of said spline means.

4. A chart-changing apparatus as defined in claim 2,

wherein:

each said retainer clip is formed as a circular washer open at one side thereof and with a slot having opposing flats to embrace said fiat spline surfaces.

5. A chart-changing apparatus as defined in claim 1, includindexing means on said chart backing plate adapted to align all charts to a common position, including a pin outstanding from said chart backing plate and adapted to engage an opening in a chart.

6. A chart-changing apparatus as defined in claim 1,

wherein said actuator means includes:

a pusher having an arcuate flange and mounted in position for movement toward a series of charts on said arbor, said arcuate flange engaging the outermost chart above the open side of the outermost retainer clip; and

means for moving said pusher toward said charts.

7. A chart-changing apparatus as defined in claim 6,

wherein:

said arcuate flange extends from the upper edge of a transverse, upright member; and

an open top container for receiving each outermost clip as it drops from said arbor is supported by said upright member.

8. A chart-changing apparatus as defined in claim 6,

wherein:

said pusher is moved toward said chart backing plate by a plunger;

said plunger is moved toward said charts by a fluid-operated piston; and

the supply of fluid to said piston is controlled by a solenoid.

9. A chart-changing apparatus as defined in claim 1,

wherein said activating means includes:

1 a cam mounted upon the aforesaid drive shaft and having an oflset at a position corresponding to said predetermined position;

a switch having a follower engaging said cam and adapted to actuate said switch when engaging said offset; and

means responsive to said switch for controlling said actuator means.

10. A chart-changing apparatus as defined in claim 9,

wherein:

said switch has a normally open contact which is closed when said follower engages said offset in said cam disc and a normally closed contact which is opened when said follower engages said offset but is again closed as said follower leaves said offset;

a battery is connected at one side to said normally open contact of said switch;

a capacitor is connected between said switch and the op-' posite side of said battery;

a relay coil controlling a normally open relay switch is connected between said opposite side of said battery and said normally closed contact; and

a solenoid coil for controlling the movement of said actuator means is connected in series with said relay switch and the opposite sides of said battery.

11. A chart-changing apparatus as defined in claim 10,

wherein:

said actuating means includes a pusher mounted on a plunger, said pusher being constructed and arranged to engage the outermost chart and simultaneously clear the outermost retainer clip; and

said plunger is the core of a solenoid including said solenoid coil.

12. A unit for substitution in a chart-changing apparatus adapted to be mounted upon the drive shaft of the timing motor of a recorder and to hold a series of charts for marking in turn by a recorder pen or the like as the charts are rotated by the motor, said unit comprising:

an arbor having spline means and a rear hub;

a chart backing plate mounted upon said arbor, having a central aperture engageable with said arbor and key means permitting said chart backing plate to move longitudinally along said arbor but causing said chart backing plate to rotate with said arbor;

a compression spring surrounding said arbor and engaging said hub at one end and said chart backing plate at the opposite end;

abutment means at the outer end of said arbor and interrupting the spline means; a v I a series of charts mounted on said arbor outwardly of said chart backing plate, each chart having a central hole which permits the chart to move over said abutment means; and

a series of retainer clips interspaced with said charts, each said clip having means engaging said spline means and means which permits the outermost clip to fall away from the arbor when the arbor is rotated to a predetennined position and the pressure of said spring holding said outermost clip against said abutment means is relieved.

13. Apparatus for changing charts in a rotating chart recorder having a chart drive shaft rotated by a timing motor, comprising:

a. an arbor having spline means thereon, said arbor being adapted to be mounted upon said chart drive shaft to extend therefrom; Y

b. an abutment located at the termination of said spline means on the outer end of said arbor, said abutment permitting charts with a mounting hole to be moved on to and off said arbor from the outer end thereof;

c. means for urging charts disposed on said arbor toward said abutment;

d. a series of retainer clips adapted to be interspaced with charts disposed on said arbor, each of said retainer clips engaging said spline means so as to rotate with said arbor and move longitudinally along said arbor and having means to permit the clip to fall away from said arbor under conditions including that when the arbor is rotated to a predetermined position, said clips being normally held in position on said arbor by said means urging charts toward said abutment; and

e. actuating means for moving charts on said arbor away from said abutment to release the pressure holding the outermost retainer clip against said abutment when said arbor is in said predetermined position, so as to release the outermost clip from said arbor, and for releasing the charts thereby permitting the outermost chart to drop ofi' the outer end of said arbor and the next outermost clip to be urged against said abutment.

14. Apparatus as defined in claim 13 wherein said means for urging charts disposed on said arbor toward said abutment comprises:

a. a chart backing plate fitted upon said arbor and constructed and arranged to rotate with said arbor and to move longitudinally along said arbor to or from said abutment; and

b. means for biasing said chart backing plate toward said abutment.

15. Apparatus as defined in claim 13 wherein said actuating means comprises means adapted to engage the outermost chart disposed on said arbor but avoid contact with the outermost retaining clip.

16. Apparatus as defined in claim 13 wherein each of said retainer clips is a substantially U-shaped member having inner parallel surfaces adapted to engage said spline means.

17. Apparatus as defined in claim 14 further including an indexing means on said chart backing plate adapted to align all charts on said arbor to common position.

18. Apparatus as defined in claim 17 wherein said indexing means comprises a pin outstanding from said chart backing plate and adapted to engage an opening in a chart.

19. Apparatus as defined in claim 13 wherein said actuating means comprises:

a. a pusher means;

b. an arcuate flange carried by said pusher means and adapted to engage the outermost chart on said arbor above the open sides of the outermost retainer clip.

20. Apparatus as defined in claim 19 further including an open top container suspended below said arcuate flange for receiving each outermost retainer clip as it drops from said arbor.

21. Apparatus as defined in claim 13 wherein said actuating means comprises:

a. a solenoid for moving said pusher means;

b. an electrical power supply;

c. a switch coupled between said electrical power supply and said solenoid;

d. means coupled to said switch and responsive to the rotational position of said chart drive shaft for actuating said switch when said chart drive shaft is rotated to said predetermined position thereby completing the circuit between said electrical power supply and said solenoid to move said pusher means into engagement with charts on said arbor.

22. Apparatus as defined in claim 21 wherein said means responsive to predetermined position of said drive shaft comprises:

a. a cam mounted on said drive shaft having an offset at a position corresponding to said predetermined position; and

b. a switch having a follower engaging said cam and adapted to actuate said switch when engaging said offset.

23. Apparatus as defined in claim 21 wherein said pusher means is mounted to the core of said solenoid.

24. Apparatus as defined in claim 21 wherein said actuating means comprises:

a. a fluid-actuated piston for moving said pusher means toward said chart backing plate;

b. a fluid line coupled to said fluid-actuated piston for supplying fluid pressure thereto.

25. Apparatus for changing charts in a rotating chart recorder having a chart drive shaft rotated by a timing motor, comprising:

a. an arbor having a pair of spline surfaces thereon;

b. an abutment formed at the outer end of said arbor and a mounting opening to be moved on to and off said arbor backing plate toward said abutment; g. a series of retainer clips adapted to be mterspaced with charts disposed on said arbor, each of said retainer clips having a slot for engaging said spline surfaces to rotate with said arbor but move longitudinally along said arbor,

each of said retainer clips being open at one end of said slot to permit falling away from said arbor when said arbor is rotated to a predetermined position and the pressure of said spring holding the outermost clip against the abutment is released;

h. a plunger mounted for axial movement in line with said arbor toward said chart backing plate;

. a chart-engaging foot mounted at the tip of said plunger for engaging the outermost chart of a group of charts. disposed on said arbor, said chart-engaging foot comprising an arcuate flange which contacts the outermost chart but clears contact with the outermost retainer clip when said retainer clip is oriented in said predetermined position; and

. means for rapidly actuating said plunger to engage the outermost chart disposed on said arbor and release the tension holding the outermost retainer clip against said abutment when said output drive shaft rotates to a predetermined position and for retracting said plunger after said outermost clip has had sufficient time to fall away from said arbor.

26. A unit for substitution in an apparatus for changing charts in a rotating chart recorder having a chart drive shaft rotated by a timing motor, comprising:

a. an arbor having spline means thereon, said arbor adapted to be mounted upon said chart drive shaft to extend therefrom;

b. an abutment formed at the outer end of said arbor interrupting said spline means, but permitting charts with a mounting hole to be moved on to and ofi said arbor from the outer end thereof; I

c. a series of charts mounted on said arbor;

(1. means carried by said arbor for urging said charts toward said abutment; and

e. a series of retainer clips interspaced with said charts on said arbor, each of said clips having means engaging said spline means so as to rotate with said arbor and having means which permits the outermost clip to fall away from said arbor when said arbor is rotated to a predetermined position and the pressure holding the outermost clip against said abutment is relieved.

27. A unit as defined in claim 26 wherein said means for urging charts toward said abutment comprises:

a. a chart backing plate fitted upon said arbor and constructed and arranged to rotate with said arbor and to move longitudinally along said arbor to or from said abutment; and

b. a spring carried by said arbor for biasing said chart backing plate toward said abutment.

. UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,638,236 I Dated January 25, 1972 Inventor(s) Bobby D. Adams It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The name of the assignee should read -Tejas Instrument Engineers, Inc.. Column 3, line 19, "pine" should read pin-; line 72, "Shown" should read -described.

Column 4, line 33, "he" should read the-; line 43, "he" should read .the-. Column 6, line 42, "Have" should read --I -have.

Signed and sealed this 15th day of August'l972.

(SEAL) Attest:

EDWARD MELETCHERJR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents [Q50 O USCOMM-DC 60376-P69 U.S GOVERNMENT PRINTING OFFICE I969 0-366-334 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTEUN Patent No. 3 Dated January 25, 1972 Inventor(s) Bobby D. Adams It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The name of the assignee should read -Tejas Instrument Engineers, Inc.. Column 3, line 19, "pine" should read pin-; line 72, "Shown" should read -described--. Column 4 line 33, "he" should read -the; line 43, "he" should read -the-. Column 6 line 42 "Have" should read --I -have-.

Signed and sealed this 15th day of August '1972.

(SEAL) Attest:

EDWARD M .FLETCHER JR ROBERT GOTTSCHALK Attesting Officer- Commissioner of Patents USCOMM-DC GOING-P69 fi u.s GOVERNMENT PRINTING OFFICE 1969 0-356-334 

1. A chart-changing apparatus adapted to be mounted upon the output drive shaft of the timing motor of a recorder and to hold a series of charts for marking in turn by a recorder pen or the like as the charts are rotated by the motor, the combination comprising: a. an arbor having spline means thereon, said arbor being adapted to be mounted upon said drive shaft to extend therefrom; b. abutment means at the outer end of the arbor interrupting the spline means but permitting charts with a central hole to be moved onto and off the arbor from the outer end thereof; c. a chart backing plate fitted upon the arbor and constructed and arranged so as to rotate with the arbor and to move longitudinally along the arbor to or from said abutment means; d. means for biasing said chart backing plate towards said abutment means; e. a series of retainer clips adapted to be interspaced with charts disposed on said arbor, each said clip having means engaging said spline means so as to rotate with the arbor and move longitudinally along the arbor and means to permit the clip to fall away from the arbor under conditions including that when the arbor is rotated to a predetermined position, said clips being normally held in position on the arbor by the pressure of said biasing means urging the outermost clip against the abutment means; f. actuator means for pushing charts disposed on said arbor away from said abutment means to release the pressure holding the outermost clip against said abutment means; and g. means for activating said actuator means when said retainer clips and arbor are in said predetermined position, so as to release the outermost clip from the arbor, said biasing means causing the outermost chart to drop off the outer end of the arbor upon a return movement of said actuator means and urging the next outermost clip against said abutment means, so as to hold the remaining charts and clips upon the arbor.
 2. A chart-changing apparatus as defined in claim 1, wherein: said spline means comprise flat surfaces on opposite sides of the arbor and disposed in spaced parallelism.
 3. A chart-changing apparatus as defined in claim 2, wherein: said abutment means comprises an annular shoulder at the termination of said spline means; and a ring mounted on said shoulder, said ring extending laterally beyond the surfaces of said spline means.
 4. A chart-changing apparatus as defined in claim 2, wherein: each said retainer clip is formed as a circular washer open at one side thereof and with a slot having opposing flats to embrace said flat spline surfaces.
 5. A chart-changing apparatus as defined in claim 1, including: indexing means on said chart backing plate adapted to align all charts to a common position, including a pin outstanding from said chart backing plate and adapted to engage an opening in a chart.
 6. A chart-changing apparatus as defined in claim 1, wherein said actuator means includes: a pusher having an arcuate flange and mounted in position for movement toward a series of charts on said arbor, said arcuate flange engaging the outermost chart above the open side of the outermost retainer clip; and means for moving said pusher toward said charts.
 7. A chart-changing apparatus as defined in claim 6, wherein: said arcuate flange extends from the upper edge of a transverse, upright member; and an open top container for receiving each outermost clip as it drops from said arbor is supported by said upright member.
 8. A chart-changing apparatus as defined in claim 6, wherein: said pusher is moved toward said chart backing plate by a plunger; said plunger is moved toward said charts by a fluid-operated piston; and the supply of fluid to said piston is controlled by a solenoid.
 9. A chart-changing apparatus as defined in claim 1, wherein said activating means includes: a cam mounted upon the aforesaid drive shaft and having an offset at a position corresponding to said predetermined position; a switch having a follower engaging said cam and adapted to actuate said switch when engaging said offset; and means responsive to said switch for controlling said actuator means.
 10. A chart-changing apparatus as defined in claim 9, wherein: said switch has a normally open contact which is closed when said follower engages said offset in said cam disc and a normally closed contact which is opened when said follower engages said offset but is again closed as said follower leaves said offset; a battery is connected at one side to said normally open contact of said switch; a capacitor is connected between said switch and the opposite side of said battery; a relay coil controlling a normally open relay switch is connected between said opposite side of said battery and said normally closed contact; and a solenoid coil for controlling the movement of said actuator means is connected in series with said relay switch and the opposite sides of said battery.
 11. A chart-changing apparatus as defined in claim 10, wherein: said actuating means includes a pusher mounted on a plunger, said pusher being constructed and arranged to engage the outermost chart and simultaneously clear the outermost retainer clip; and said plunger is the core of a solenoid including said solenoid coil.
 12. A unit for substitution in a chart-changing apparatus adapted to be mounted upon the drive shaft of the timing motor of a recorder and to hold a series of charts for marking in turn by a recorder pen or the like as the charts are rotated by the motor, said unit comprising: an arbor having spline means and a rear hub; a chart backing plate mounted upon said arbor, having a central aperture engageable with said arbor and key means permitting said chart backing plate to move longitudinally along said arbor but causing said chart backing plate to rotate with said arbor; a compressiOn spring surrounding said arbor and engaging said hub at one end and said chart backing plate at the opposite end; abutment means at the outer end of said arbor and interrupting the spline means; a series of charts mounted on said arbor outwardly of said chart backing plate, each chart having a central hole which permits the chart to move over said abutment means; and a series of retainer clips interspaced with said charts, each said clip having means engaging said spline means and means which permits the outermost clip to fall away from the arbor when the arbor is rotated to a predetermined position and the pressure of said spring holding said outermost clip against said abutment means is relieved.
 13. Apparatus for changing charts in a rotating chart recorder having a chart drive shaft rotated by a timing motor, comprising: a. an arbor having spline means thereon, said arbor being adapted to be mounted upon said chart drive shaft to extend therefrom; b. an abutment located at the termination of said spline means on the outer end of said arbor, said abutment permitting charts with a mounting hole to be moved on to and off said arbor from the outer end thereof; c. means for urging charts disposed on said arbor toward said abutment; d. a series of retainer clips adapted to be interspaced with charts disposed on said arbor, each of said retainer clips engaging said spline means so as to rotate with said arbor and move longitudinally along said arbor and having means to permit the clip to fall away from said arbor under conditions including that when the arbor is rotated to a predetermined position, said clips being normally held in position on said arbor by said means urging charts toward said abutment; and e. actuating means for moving charts on said arbor away from said abutment to release the pressure holding the outermost retainer clip against said abutment when said arbor is in said predetermined position, so as to release the outermost clip from said arbor, and for releasing the charts thereby permitting the outermost chart to drop off the outer end of said arbor and the next outermost clip to be urged against said abutment.
 14. Apparatus as defined in claim 13 wherein said means for urging charts disposed on said arbor toward said abutment comprises: a. a chart backing plate fitted upon said arbor and constructed and arranged to rotate with said arbor and to move longitudinally along said arbor to or from said abutment; and b. means for biasing said chart backing plate toward said abutment.
 15. Apparatus as defined in claim 13 wherein said actuating means comprises means adapted to engage the outermost chart disposed on said arbor but avoid contact with the outermost retaining clip.
 16. Apparatus as defined in claim 13 wherein each of said retainer clips is a substantially U-shaped member having inner parallel surfaces adapted to engage said spline means.
 17. Apparatus as defined in claim 14 further including an indexing means on said chart backing plate adapted to align all charts on said arbor to common position.
 18. Apparatus as defined in claim 17 wherein said indexing means comprises a pin outstanding from said chart backing plate and adapted to engage an opening in a chart.
 19. Apparatus as defined in claim 13 wherein said actuating means comprises: a. a pusher means; b. an arcuate flange carried by said pusher means and adapted to engage the outermost chart on said arbor above the open sides of the outermost retainer clip.
 20. Apparatus as defined in claim 19 further including an open top container suspended below said arcuate flange for receiving each outermost retainer clip as it drops from said arbor.
 21. Apparatus as defined in claim 13 wherein said actuating means comprises: a. a solenoid for moving said pusher means; b. an electrical power supply; c. a switch coupled between said electrical power supply and said solenoid; d. means coupled to said swItch and responsive to the rotational position of said chart drive shaft for actuating said switch when said chart drive shaft is rotated to said predetermined position thereby completing the circuit between said electrical power supply and said solenoid to move said pusher means into engagement with charts on said arbor.
 22. Apparatus as defined in claim 21 wherein said means responsive to predetermined position of said drive shaft comprises: a. a cam mounted on said drive shaft having an offset at a position corresponding to said predetermined position; and b. a switch having a follower engaging said cam and adapted to actuate said switch when engaging said offset.
 23. Apparatus as defined in claim 21 wherein said pusher means is mounted to the core of said solenoid.
 24. Apparatus as defined in claim 21 wherein said actuating means comprises: a. a fluid-actuated piston for moving said pusher means toward said chart backing plate; b. a fluid line coupled to said fluid-actuated piston for supplying fluid pressure thereto.
 25. Apparatus for changing charts in a rotating chart recorder having a chart drive shaft rotated by a timing motor, comprising: a. an arbor having a pair of spline surfaces thereon; b. an abutment formed at the outer end of said arbor and terminating said spline surfaces but permitting charts with a mounting opening to be moved on to and off said arbor from the outer end thereof; c. a hub on the inner end of said arbor; d. a chart backing plate mounted upon said arbor; e. a key and keyway on said chart backing plate and said arbor to permit said chart backing plate to move longitudinally along said arbor but causing said chart backing plate to rotate with said arbor; f. a compression spring surrounding said arbor between said rear hub and said chart backing plate for urging said chart backing plate toward said abutment; g. a series of retainer clips adapted to be interspaced with charts disposed on said arbor, each of said retainer clips having a slot for engaging said spline surfaces to rotate with said arbor but move longitudinally along said arbor, each of said retainer clips being open at one end of said slot to permit falling away from said arbor when said arbor is rotated to a predetermined position and the pressure of said spring holding the outermost clip against the abutment is released; h. a plunger mounted for axial movement in line with said arbor toward said chart backing plate; i. a chart-engaging foot mounted at the tip of said plunger for engaging the outermost chart of a group of charts disposed on said arbor, said chart-engaging foot comprising an arcuate flange which contacts the outermost chart but clears contact with the outermost retainer clip when said retainer clip is oriented in said predetermined position; and j. means for rapidly actuating said plunger to engage the outermost chart disposed on said arbor and release the tension holding the outermost retainer clip against said abutment when said output drive shaft rotates to a predetermined position and for retracting said plunger after said outermost clip has had sufficient time to fall away from said arbor.
 26. A unit for substitution in an apparatus for changing charts in a rotating chart recorder having a chart drive shaft rotated by a timing motor, comprising: a. an arbor having spline means thereon, said arbor adapted to be mounted upon said chart drive shaft to extend therefrom; b. an abutment formed at the outer end of said arbor interrupting said spline means, but permitting charts with a mounting hole to be moved on to and off said arbor from the outer end thereof; c. a series of charts mounted on said arbor; d. means carried by said arbor for urging said charts toward said abutment; and e. a series of retainer clips interspaced with said charts on said arbor, each of said clips having means engaging said spline means so as to rotate with said arbor and having means whiCh permits the outermost clip to fall away from said arbor when said arbor is rotated to a predetermined position and the pressure holding the outermost clip against said abutment is relieved.
 27. A unit as defined in claim 26 wherein said means for urging charts toward said abutment comprises: a. a chart backing plate fitted upon said arbor and constructed and arranged to rotate with said arbor and to move longitudinally along said arbor to or from said abutment; and b. a spring carried by said arbor for biasing said chart backing plate toward said abutment. 